Well what covering to use depends on what you are building. On my unlimited funfly planes i use clear ultrcote where i need the covering to be able to flex with the airframe and clear monokote where i need strength. The monoktoe clear is lighter than the ultracote but its tensile strength is higher so if it is used in a high flex area it will shatter....for example if you use monokote clear in the center section of a weakly built stick and boom aircraft then when you start banging out loop touch and go's the monokote will shatter in the center section from the wing flexing downward when touching the ground. On the other hand Micafilm is the lightest and strongest stuff i have ever used but some what more time consuming to install because you have to paint the glue onto your airframe before you can cover it.